In general, a pretreatment device for a sample in chemical analysis is configured of combination of a plurality of modules that carry out processes of pretreatment. The processes of the pretreatment include, for example, a process of adding and mixing a reagent to a sample, a process of heating a sample liquid to which the reagent is added, and the like. As an analysis device including such a pretreatment device, a device disclosed in PTL 1 has been known.
In PTL 1, there are provided, in a first flow path from the upstream side, a first sample introducing unit for mixing a sample and a reagent, a pretreatment unit that carries out thermolysis of a reagent-mixed sample liquid in a constant-temperature oven, a second sample introducing unit that introduces the sample liquid obtained after the thermolysis and causes the sample liquid to flow in a loop having a length of a flow path which varies depending on concentration of the sample. Further, a coloring unit that introduces the sample liquid from the second sample introducing unit through a second flow path and adds a coloring reagent thereto, and a detection unit that detects the sample liquid to which the coloring reagent is added are included.